AbstractThis article analyzes the initial effect of introducing a cooperative catch shares allocation system (CCS) on the technical efficiency of artisanal vessels operating in pelagic fisheries in south-central Chile. The voluntary nature of the system implies that some fishermen adopted the CCS and others did not, generating in the latter a natural control group for evaluating the effect of the regulation. We used the stochastic frontier model to estimate technical inefficiency and a difference-in-difference approach to identify the effect of the regulatory change on the performance of vessels that joined the CCS, while controlling for the behavior of the vessels that remained in the “common pool system.” The introduction of cooperative catch shares in the sardine and anchovy fishery reduced technical efficiency in the vessels that adopted the CCS, on average. However, the impact on fisherman’s technical efficiency was heterogeneous depending on the characteristics of the fishermen’s organization. This ...